I haven't done it a bunch but have on and off for various MtnGFX projects in the past.

In 7 it's a bit easier. There's a tutorial on this site somewhere about doing this. I haven't looked at it though so I don't know anything about it.

What I do: after scene is ready for export to AE...

1. Point contrain a locator to moving objects and the camera (Try a 1 node camera first for practice)

2. Then bake the keys for these locators and bake the keys for the camera. Only need TRS ~ trans, rot, scale.

3. Export the locators for cameras and objects that were previous baked, out into a new scene file.

4. Open this file, clean it up of unneccessary nodes and save the file as an ASCII *.ma file from Maya.

5. Import in AE and select your Maya ma file and you should be good to go.

99% of the time I use an psuedo HD frame of 1280x720 and this coincidentally requires little DOF and lens adjustment.

If your lense is telephoto, wide etc. you need to do some further online searching to learn how to sync up your Maya cam lense and AE's but often times but importing your Maya.ma file (Not MB), AE will adjust it's camera lens to be close but sometimes it's not and that frankly is close to unsolvable (At least by me).